Conventionally, it has been known to use a body fluid suction reservoir in order to suck in and evacuate body fluid from a wound cavity of a human body. In this case, one end of a tube is inserted into the wound cavity to evacuate and lead the body fluid, and the other end of the tube is connected to a suction reservoir, whereby the body fluid in the wound cavity is collected and stored in the suction reservoir by negative pressure generated in the suction reservoir.
As a mechanism for generating the negative pressure in the suction reservoir, there have been known a mechanism disclosed in JP-A-57-81346 in which a container with an extensible elastic member built-in (such as a spring, or rubber) is previously compressed, in other words, the elastic member is contracted to previously reduce the internal volumetric capacity, so that negative pressure is generated in the container due to restoring force of the elastic member to suck in and collect body fluid, and a mechanism disclosed in JP-A-50-84090 and 61-131751 for example, in which an expandable and extensible elastic member (a balloon or a diaphragm, for example) is provided in a rigid container, and is previously expanded by exhausting gas from the rigid container using internal air supply, exhaust, or other dynamic means, so that negative pressure is generated in the container due to contractive force of the elastic member to suck in and collect body fluid.
Since the former mechanism starts to suck in a state where the container is squashed, it is very compact especially at the beginning of the suction in comparison with the latter mechanism, and has an advantage that it is superior in portability because it does not take much space when it is set to a patient. Further, the former mechanism is provided with a lock means for keeping the container in the squashed state and thus, can contribute to reducing the transferring and storing costs thereof. However, since the suction apparatus disclosed in JP-A-57-81346 is made to release the lock means by folding a hinge portion of a plate, there is a possibility that the lock may be easily released due to external force even in a state where the suction apparatus is packaged or baled in transit or storage. Further, since hooks provide on two plates are configured to engaged with each other, which is advantageous in terms of manufacturing cost and space saving, there is a problem that the hooks cannot be locked due to creep deformation after repeated use.